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Q 1: Which couldpotentially cause you the greater injury; being tackled by aligh

ID: 1678315 • Letter: Q

Question

Q 1:

Which couldpotentially cause you the greater injury; being tackled by alight-weight,

fast-moving footballplayer, or being tackled by a player with double the massbut

moving at half thespeed? Marks =5

Q 2:

For each situation,state whether the collision is elastic or inelastic. If it isinelastic, state

whether it iscompletely inelastic or not?

a) You drop a ballfrom your hand. It collides with the floor and bounces back upso

that it just reachesyour hand.

b) You drop adifferent ball from your hand and let it collide with the ground.This

ball bounces back upto half the height from which it was dropped.

c) You drop a ball ofclay from your hand. When it collides with the ground, itstops.

Marks =5

2

Q 3:

Will the centre ofmass in Fig, 1 continue on the same parabolic trajectory even afterone

of the fragments hitsthe ground? Why or why not? Marks = 5

Fig 1. A shellexplodes into two fragments in flight. If air is ignored, thecentre of mass

continues on the sametrajectory as the shell’s path before exploding.

Q 4:

(a)If a rocket ingravity- free outer space has the same thrust at all times, isits

acceleration constant,increasing or decreasing?

(b) If the rocket hasthe same acceleration at all times, is the thrust constant,increasing or

decreasing?

Explanation / Answer

Q1.   Both will cause me same amount of injury. In thefirst case, let the mass of the first football player is M & hewas moving at a speed of V. Now, The momentum of that player is =MV Now, in case of the 2nd football player with double the mass buthalf the speed, the momnetum is: (M/2).(2V)=MV. so, its the same. Hence both will cause me same injury. Q2. a)elastic.        b)inelastic.    c) Completely inelastic.